233 lines
4.6 KiB
ArmAsm
233 lines
4.6 KiB
ArmAsm
/* Pentium optimized __mpn_rshift --
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Copyright (C) 1992, 94, 95, 96, 97, 98, 2000 Free Software Foundation, Inc.
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This file is part of the GNU MP Library.
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The GNU MP Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or (at your
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option) any later version.
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The GNU MP Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the GNU MP Library; see the file COPYING.LIB. If not, write to
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the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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MA 02111-1307, USA. */
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#include "sysdep.h"
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#include "asm-syntax.h"
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#include "bp-sym.h"
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#include "bp-asm.h"
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#define PARMS LINKAGE+16 /* space for 4 saved regs */
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#define RES PARMS
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#define S RES+PTR_SIZE
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#define SIZE S+PTR_SIZE
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#define CNT SIZE+4
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.text
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ENTRY (BP_SYM (__mpn_rshift))
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ENTER
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pushl %edi
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pushl %esi
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pushl %ebp
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pushl %ebx
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movl RES(%esp),%edi
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movl S(%esp),%esi
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movl SIZE(%esp),%ebx
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movl CNT(%esp),%ecx
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#if __BOUNDED_POINTERS__
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shll $2, %ebx /* convert limbs to bytes */
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CHECK_BOUNDS_BOTH_WIDE (%edi, RES(%esp), %ebx)
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CHECK_BOUNDS_BOTH_WIDE (%esi, S(%esp), %ebx)
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shrl $2, %ebx
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#endif
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/* We can use faster code for shift-by-1 under certain conditions. */
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cmp $1,%ecx
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jne L(normal)
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leal 4(%edi),%eax
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cmpl %esi,%eax
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jnc L(special) /* jump if res_ptr + 1 >= s_ptr */
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leal (%edi,%ebx,4),%eax
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cmpl %eax,%esi
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jnc L(special) /* jump if s_ptr >= res_ptr + size */
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L(normal):
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movl (%esi),%edx
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addl $4,%esi
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xorl %eax,%eax
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shrdl %cl,%edx,%eax /* compute carry limb */
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pushl %eax /* push carry limb onto stack */
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decl %ebx
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pushl %ebx
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shrl $3,%ebx
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jz L(end)
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movl (%edi),%eax /* fetch destination cache line */
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ALIGN (2)
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L(oop): movl 28(%edi),%eax /* fetch destination cache line */
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movl %edx,%ebp
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movl (%esi),%eax
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movl 4(%esi),%edx
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shrdl %cl,%eax,%ebp
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shrdl %cl,%edx,%eax
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movl %ebp,(%edi)
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movl %eax,4(%edi)
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movl 8(%esi),%ebp
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movl 12(%esi),%eax
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shrdl %cl,%ebp,%edx
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shrdl %cl,%eax,%ebp
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movl %edx,8(%edi)
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movl %ebp,12(%edi)
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movl 16(%esi),%edx
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movl 20(%esi),%ebp
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shrdl %cl,%edx,%eax
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shrdl %cl,%ebp,%edx
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movl %eax,16(%edi)
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movl %edx,20(%edi)
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movl 24(%esi),%eax
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movl 28(%esi),%edx
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shrdl %cl,%eax,%ebp
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shrdl %cl,%edx,%eax
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movl %ebp,24(%edi)
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movl %eax,28(%edi)
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addl $32,%esi
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addl $32,%edi
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decl %ebx
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jnz L(oop)
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L(end): popl %ebx
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andl $7,%ebx
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jz L(end2)
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L(oop2):
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movl (%esi),%eax
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shrdl %cl,%eax,%edx /* compute result limb */
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movl %edx,(%edi)
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movl %eax,%edx
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addl $4,%esi
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addl $4,%edi
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decl %ebx
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jnz L(oop2)
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L(end2):
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shrl %cl,%edx /* compute most significant limb */
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movl %edx,(%edi) /* store it */
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popl %eax /* pop carry limb */
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popl %ebx
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popl %ebp
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popl %esi
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popl %edi
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LEAVE
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ret
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/* We loop from least significant end of the arrays, which is only
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permissible if the source and destination don't overlap, since the
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function is documented to work for overlapping source and destination.
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*/
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L(special):
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leal -4(%edi,%ebx,4),%edi
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leal -4(%esi,%ebx,4),%esi
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movl (%esi),%edx
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subl $4,%esi
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decl %ebx
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pushl %ebx
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shrl $3,%ebx
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shrl $1,%edx
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incl %ebx
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decl %ebx
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jz L(Lend)
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movl (%edi),%eax /* fetch destination cache line */
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ALIGN (2)
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L(Loop):
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movl -28(%edi),%eax /* fetch destination cache line */
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movl %edx,%ebp
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movl (%esi),%eax
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movl -4(%esi),%edx
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rcrl $1,%eax
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movl %ebp,(%edi)
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rcrl $1,%edx
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movl %eax,-4(%edi)
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movl -8(%esi),%ebp
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movl -12(%esi),%eax
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rcrl $1,%ebp
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movl %edx,-8(%edi)
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rcrl $1,%eax
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movl %ebp,-12(%edi)
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movl -16(%esi),%edx
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movl -20(%esi),%ebp
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rcrl $1,%edx
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movl %eax,-16(%edi)
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rcrl $1,%ebp
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movl %edx,-20(%edi)
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movl -24(%esi),%eax
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movl -28(%esi),%edx
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rcrl $1,%eax
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movl %ebp,-24(%edi)
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rcrl $1,%edx
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movl %eax,-28(%edi)
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leal -32(%esi),%esi /* use leal not to clobber carry */
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leal -32(%edi),%edi
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decl %ebx
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jnz L(Loop)
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L(Lend):
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popl %ebx
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sbbl %eax,%eax /* save carry in %eax */
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andl $7,%ebx
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jz L(Lend2)
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addl %eax,%eax /* restore carry from eax */
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L(Loop2):
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movl %edx,%ebp
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movl (%esi),%edx
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rcrl $1,%edx
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movl %ebp,(%edi)
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leal -4(%esi),%esi /* use leal not to clobber carry */
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leal -4(%edi),%edi
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decl %ebx
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jnz L(Loop2)
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jmp L(L1)
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L(Lend2):
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addl %eax,%eax /* restore carry from eax */
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L(L1): movl %edx,(%edi) /* store last limb */
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movl $0,%eax
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rcrl $1,%eax
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popl %ebx
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popl %ebp
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popl %esi
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popl %edi
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LEAVE
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ret
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END (BP_SYM (__mpn_rshift))
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